WRONG.
You cannot be “ONE”, as Jesus and the Father are ONE (John 17:20-23) when you have thousands of factions teaching all sorts of different doctrines – some as different as night and day.
Some Protestant denominations believe in baptismal regeneration, while others do not.
Some believe in soul-sleep, while others do not.
Some believe in the total depravity of man, while others do not.
Some believe in the Holy Trinity, while others do not.
Some believe in doctrine of “once saved, always saved”, while others do not.
Some believe in a pre-tribulation “Rapture”, while others do not.
Some believe that only those who were predestined will make it to heaven, while others do not.
Some believe that some were predestined for hell, while others do not.
Some believe in a woman’s right to choose abortion, while others do not.
Some believe that practicing homosexuality is a sin, while others do not.
Most believe in contraception, while others do not – and the list goes on . . .
This is PRECISELY the type of disunity and factionism that Paul preached against (1 Cor. 1:10-17).
On the contrary, he talked about being of ONE MIND in ALL things:
1 Cor. 1:13
Is Christ divided? Was Paul crucified for you? Were you baptized in the name of Paul?
1 Cor. 1:10
I appeal to you, brothers and sisters, in the name of our Lord Jesus Christ, that all of you agree with one another in what you say and that there be no divisions among you, but that you be PERFECTLY UNITED IN MIND AND THOUGHT.
Phil;. 2:1-4
Therefore if you have any encouragement from being united with Christ, if any comfort from his love, if any common sharing in the Spirit, if any tenderness and compassion, then make my joy complete by being like-minded, having the SAME love, being ONE in spirit and of ONE mind. Do nothing out of selfish ambition or vain conceit. Rather, in humility value others above yourselves, not looking to your own interests but each of you to the interests of the others
NOWHERE, do I see in ANY of these verses the consent to change or twist doctrines based on someone’s own personal views.
NOWHERE, do I see permission for congregations or individuals to break off from each other when someone disagrees.
If you’re NOT united in mind and thought – you’re NOT part of His Church.